Partially blocking a chimney

Grenage

We have an open chimney that I am keen to keep; we like the occasional fire for atmosphere. We have no free source of wood, so I'm no interested in installing a stove.

The chimney is open at the top (no pot), and ventilation is obviously required to keep it dry - but a fair amount of heat goes up and out all day every day.

Has anyone used one of the partial blocking devices such as a chimney sheep? I could easily make my own version using a bag of insulation with a waste pipe through the middle. Would a 40mm gap be enough airflow for the stack?

Doozergirl

If the insulation is loosely pushed up then there will be some air gaps anyway.

Cap the top so birds and rain don't get in, but air can.

Grenage

Doozergirl wrote: »

If the insulation is loosely pushed up then there will be some air gaps anyway.

Cap the top so birds and rain don't get in, but air can.

Cheers! I might get someone in for that; I don't much fancy 10 metres up on a ladder.

FreeBear

Doozergirl wrote: »

Cap the top so birds and rain don't get in, but air can.

But as the OP intends to light the occasional fire, capping the pot probably isn't a good idea. I'd suggest a simple mesh cowl as used with many wood stoves. It will stop birds & maost of the rain from getting in, yet still allow use of the (open) fire when needed.

Grenage

Hi FreeBear. I assumed DoozerGirl meant a clay cowl or the like, but yes you're correct, we occasionally use it so I wouldn't want to close it completely.

Doozergirl

Grenage wrote: »

Hi FreeBear. I assumed DoozerGirl meant a clay cowl or the like, but yes you're correct, we occasionally use it so I wouldn't want to close it completely.

I did. I couldn't remember the word at all